Tetrakis(polyfluoromethyl)-4-oxazolidinones

ABSTRACT

DESCRIBED ARE 4-OXAZOLIDINONES HAVING ACYLIC POLYHALOMETHYL SUBSTITUTENTS CONTAINING SOME FLUORINE IN THE 2- AND 5-POSITIONS, E. G, 2,5-BIS(DIFLUOROMETHYL)-2,5-BIS(TRIFLUOROMETHYL)-4-OXAZOLIDINONE. THESE COMPOUNDS EXHIBIT STRONG HERBICALDAL ACTION.

6 Umted States Patent O ce Patented Jan. 23, 1973 or the tautomeric Formula H: 3,712,902 A TETRAKIS(POLYFLUOROMETHYL)-4- O OXAZOLIDINONES E William J. Middleton, Wilmington, Del., assignor to E. I. du Pont de Nemours and Company, Wilmington, Del. 2 No Drawing. Continuation-impart of application Ser. No. I

636,019, May 4, 1967. This application Aug. 5, 1969, Ser. No. 847,723 g} The portion of the term of the patent subsequent to Mar. zX (II) $1, 1984, has been disclaimed and dedicated to the h i ublic Int CL 3 7 5 30 5 3 X X X and X are alike or difierent and are hydro- U.S. Cl. 260--307 A 4 Claims gen, fluorine or chlorine, with the proviso that at least one X be other than fluorine; and A is hydrogen, a metal of Group I-A, I-B, II-A, or lI-B ABSTRACT OF THE DISCLOSURE Described are 4-oxazolidinones having acylic polyhalomethyl substituents containing some fluorine in the 2- and 5-p0sitions, e.g., 2,5-bis(difluoromethyl)-2,5-bis(trifiuoromethyl)-4-oxazolidinone. These compounds exhibit strong herbicidal action.

RELATED APPLICATIONS BACKGROUND OF THE INVENTION (1) Field of the invention This specification relates to, and has as its principal object provision of, 4-oxazolidinones having fluoromethyl, but not more than three perfiuoromethyl, substituents in the 2- and 5-positions, useful as herbicides.

(2) Description of the prior art My US. Pat. 3,310,570 of Mar. 21, 1967, entitled, Trifluoromethyl-Substituted 4-Oxazolidiones and Their Preparation, discloses and claims 4-oxazolidones having trifluoromethyl substituents in the 2- and 5-positions. The herbicidal utility of the compounds of this application is described and claimed in my copending application Ser. No. 839,054, filed July 3, 1969. The related spiro compounds of my pending application Ser. No. 741,054, filed June 28, 1968, now US. Pat. 3,534,050, are useful against the influenza-B virus.

SUMMARY AND DESCRIPTION OF THE INVENTION The compounds of the present invention have the Formula I:

FiX

of the Periodic Table, i.e., Li, Na, K, Rb, Cs, Cu, Ag,

Au, Be, Mg, Ca, Sr, Ba, Zn, Cd, or Hg, or ammonium or substituted ammonium, i.e., NH or the Rs being the same or different and selected from the group consisting of hydrogen, alkyl having l-4 carbon atoms, and alkyl having 1-4 carbon atoms substituted with one hydroxy group.

Formulae I and II represent extremes of the actual compounds which, when A is H, are mixtures of I and II or some intermediate structure(s). When A is a cation as defined above, there is no formal linkage between said cation and the oxazolidinone which then exists as anion wherein the charge is often represented as distributed over the ET G ZSQ Thus:

9 i X 0 F: C X) Fr-C N -(.[3CFX4 Fix (III) The well-known reversible-type formula for the structure(s) present may also be used:

I 0-A X 031 d X10 F, i

x 0 F -C NA merge N S l 0 -0 Fix o -CF;X4

Fix: FtX

The compounds in which A is an alkali metal or quaternary ammonium are prepared by the reaction of at least two molecular equivalents of a polyfluoroacetone with one molecular equivalent of an alkali metal or quaternary ammonium cyanide. A representative reaction can be shown by the equation:

Equation 1 Fax where A is an alkali metal or quaternary ammonium cation in which the alkyl groups have up to 4 carbons, such as tetraethylammonium and tetrabutylammonium.

This reaction can be conducted either without solvent or in the presence of a solvent or an inert reaction medium such as a carbonitrile, ether, or hydrocarbon. A preferred action medium is acetonitrile. The temperature is not critical, and can be as low as 100 or as high as 100 C. The preferred temperature range is from 80 to 70 C. Time and pressure are also not critical. The salt need not be isolated from the reaction mixture prior to further reaction with acids. However, the salt can be isolated, if desired, by evaporation of the reaction mixture to dryness.

Mixtures of polyfluoroketones yield mixtures of oxazolidinones, e.g.:

Equation 2 zoom )1 o N s This reaction is described in detail for the preparation of 2,2,5,5-tetrakis(trifluoromethyl) 4 oxazolidinone in my above-mentioned US Pat. 3,310,570, the disclosure of which is incorporated herein by reference.

The compounds of this invention in which A is other than hydrogen, i.e., salts, can also be prepared by reaction of a compound Where A is hydrogen, i.e., hydrogen compounds, with an alkali metal or alkaline earth metal alkoxide, hydroxide or carbonate or with ammonia or an amine. Alternatively, those compounds in which A is sodium ion can be prepared by eliminating the acidification steps from the above reaction sequence of Equation 1. This latter procedure is also described in US. Pat. 3,310,570.

The salts of the 4-oxazolidones can also be prepared by metathesis of the alkali metal salts. For example, the addition of an acetonitrile solution of silver nitrate to an acetonitrile solution of the sodium salt of 2,2,5,5- tetrakis(trifluoromethyl)-4-oxazolidone at ordinary room temperature results in the precipitation of sodium nitrate leaving the desired silver salt of the 4-oxazolidone in solution. On removal of the precipitated sodium salt by filtration, the silver salt can be isolated by distillation of the solvent.

In addition to the position isomers shown in Formulae IV and V, the compounds of this invention can exist in more than one steroisomeric form. The structure of Formula I as depicted is used for brevity, but it is to be understood that is invention includes all steroisomeric variations of Formulae I and II.

EMBODIMENTS OF THE INVENTION The following examples are illustrative of the compounds of this invention and of the methods by which they can be prepared. Parts and percentages are by weight unless otherwise specified. In some examples, both parts by weight and parts by volume appear. Where the equations given stop at salt formation, the hydrogen compound is obviously formed by the addition of HCl.

EXAMPLE 1 Preparation of 2,5-bis(difluoromethyl)-2,5-bis(trifluoromethyl)-4-oxazolidinone, cis-trans mixture O 2HCFzCFs NaCN A sample of pentafiuoroacetone (50 parts by volume, measured at 78 C.) is slowly distilled into a stirred suspension of 13.44 parts of powdered sodium cyanide in 157 parts of acetonitrile. The reaction mixture is held at -30 C. during the addition (which requires about 1 hour) and for another hour; the temperature is then allowed to come to 25 C. overnight. The colorless solution is added to 200 ml. of 10% HCl and shaken. The lower organic layer is separated and washed four times with water (about 1% liter total volume) to remove acetonitrile. On the fourth washing, the product precipitates and is filtered and washed with water. The white crystalline solid is purified by recrystallization from benzene-hexane and by sublimation to give 78 parts of white crystalline 2,5 bis(difluoromethyl) 2,5 bis(trifluoromethyl)-4-oxazolidinone; M.P. 93-94 C. (sublimed); 91.5-93 C. (recrystallized). The product is identified by hydrogen and fluorine nuclear magnetic resonance spectroscopy, infrared analysis, and elemental analysis.

EXAMPLE 2 Separation of the cis and trans isomers of 2,5-bis(difluoromethyl)-2,5-bis(trifluoromethyl)-4oxazolidinone Approximately equal amounts of the pure cis and trans isomers are obtained by gas chromatographic separation on an 8-ft. column of 25% fluorosilicone on Chromosorb W at C. The following data are obtained for the two isomers:

(1) (Shorter retention time) 1 NMR (DMSO-d,,): -0.2-r (multiplet, 1H); triplets centered at 3.147 and 3.381 (1:51, Hz, 2H).

19 NMR (DMSO-d CC13F internal standard): 72.9 p.p.m. (multiplet, 3F); 78.4 p.p.m. (multiplet, 3F); 133 p.p.m. (multiplet, 4F).

(2) (Longer retention time) M.P. 93-94 C.

1;; NMR (DMSO-d triplets centered at 3.19 and 3.381- (J =5 1 Hz, 2H); NH proton not detected in 500 Hz.

scan.

19 NMR (DMSO-d CCl F internal standard): 72.6

p.p.m. (quintet, J =9 Hz, 3F); 77.9 p.p.m. (2 overlapping quartets, J =9 Hz., 1 :13 Hz., 3F); 133 p.p.m. (multiplet, 4F).

5 EXAMPLE 3 Preparation of 2,2,5,5-tetrakis (difluoromethyl)-4- oxazolidinone O HFziJ/K HFrO- e e; ZHF: -C DE NaCN A sample of s-tetrafluoroacetone (65 parts) is added portionwise during a 1-hour period of to a suspension of 12.5 parts of powdered sodium cyanide in 78 parts of acetonitrile. The temperature is maintained below 40 C. by cooling in an ice bath. After the addition, the mixture is stirred for 30 minutes, and then poured into 500 parts of water containing 68 parts of concentrated hydrochloric acid. The oily layer that separates is washed with water and dissolved in aqueous sodium hydroxide. This solution is filtered to remove undissolved material and then acidified with aqueous 5% hydrochloric acid. The solid that preciptates is collected on a filter, washed with water, and recrystallized from benzene to give 16.1 parts of the oxazolidinone as colorless needles, M.P. 122124 C. Sublimation at 120 C. (5 mm.) gives a purer product: M.P. 123-125 C.

Analysis.Calcd. for C7H5F3NO2 (percent): C, 29.28; H, 1.76; F, 52.96; N, 4.88. Found (percent): C, 29.80; H,

EXAMPLE 4 Preparation of 2-difluoromethyl-2,5,5-tris(trifluoromethyl )-4-oxazolidinone Hexafluoroacetone, 5.5 parts by volume, is distilled into a solution of 7.8 parts of tetraethylammonium cyanide in 39 parts of acetonitrile cooled to 20 C. Pentafiuoroacetone, 6 parts by volume, is then distilled into the reaction mixture at 20 C. The reaction mixture is stirred at 25 C. for 18 hours, poured into 100 parts of water, and acidified with concentrated hydrochloric acid. The organic layer is separated, dried over anhydrous magnesium sulfate and allowed to evaporate at room temperature until crystals form. The crystals are collected on a filter, recrystallized from benzene, sublimed at 135 C. (2 mm.), and resublimed at 120 C. (2 mm.) to give 8.26 parts (40% yield) of Z-difiuoromethyl-2,5,5-tris(trifluoromethyl)-4-oxazolidinone; M.P. 100-101 C.

Analysis.-Calcd. for C7F11H2NO2 (percent): C, 24.65; H, 0.59; F, 61.27; N, 4.11. Found (percent): C, 25.38; H, 1.12; F, 60.98; N, 4.88.

EXAMPLE 5 Preparation of 2,5-bis (chlorodifluoromethyl)-2,5-bis- (difiuoromethyl -4-oxazolidinone A sample of 1 chloro-1,1,3,3-tetrafiuoroacetone (46 parts) is added dropwise to a stirred solution of 21.45 parts of tetraethylammonium cyanide in 78 parts of acetonitrile at 30 C. After the addition, which requires about 20 minutes, the solution is stirred at 30 C. for 1.5 hours, then brought to room temperature over a period of 1 hour. The solution is poured into 100 ml. of 10% HCl solution, shaken, and the lower organic phase is separated and washed four times with water to remove acetonitrile. The viscous organic layer is diluted with ether and dried over MgSO and the solvent is removed by distillation. The crude product is distilled (B.P. 88l00 C. at 1.8 mm.). The nearly colorless distillate solidifies on cooling and is further purified by sublimation. A White solid (6.3 parts) is obtained: M.P. 3336 C.

Analysis.Calcd. for C H O NCl F (percent): C, 23.61; H, 0.85; N, 3.94. Found (percent): C, 23.90; H, 0.90; N, 3.89. a

EXAMPLE 6 2,5-bis(chlorodifiuoromethyl)-2,5-bis(trifluorornethyl)-4- oxazolidinone A sample of chloropentafluoroacetone (25 parts by volume) is slowly distilled into a stirred solution of 15.6 parts of tetraethylammonium cyanide in 157 parts of acetonitrile. Cooling is applied to keep the reaction temperature between 20-30 C. The reaction mixture is stirred overnight and then acidified with 200 parts of 10% hydrochloric acid. The organic layer is separated and washed several times until it becomes very viscous. It is then dissolved in 100 parts of 5% sodium hydroxide and reprecipitated by addition of 100 parts of 10% hydrochloric acid. The solid that forms upon standing is recrystallized from pentane and then sublimed at C. (10 mm.) to give 11.9 parts of the oxazolidinone as colorless crystals: M.P. 87-89 C.

Analysis.Calcd. for 0 1101 3 810, (percent): C, 21.45; H, 0.26; Cl, 18.09; F, 48.87; N, 3.57. Found (percent): C, 21.53; H, 0.33; Cl, 17.99; F, 48.43; N, 3.45.

l ClOF2COFaCl EtiNCN OlFzC By replacing the chloropentafluoroacetone of the above example with an equivalent amount of s-dichlorotetrafluoroacetone, 2,2,5,5 tetrakis(chlorodifluoromethyl)-4- 7 oxazolidinone is prepared (X =X =X =X C1; EXAMPLE 8 A Etl N). P

reparation of 2,2,5,5-tetrakls(dlfluoromethyl)- E PLE 7 4-oxazolidinone, potassium salt Prelfgratlon i .g? i To 31 parts of 2,2,5,5-tetrakis(difluoromethyl)-4-oxa- (tr uoromet y 1 mone so mm Sat zolidinone in 200 parts of water is added 100 parts by Fifteen parts of 2,5-bis(difluoromethyl)-2,5-bis(trifluovolume of 1.0 N aqueous potassium hydroxide. The rer m hy1)-4- Xazolidin ne is disso ved in 7.92 parts of sulting solution is evaporated to dryness leaving as a solid,

methanol. A solution of 2.61 parts of sodium methoxide the potassium salt of 2,2,5,5-tetrakis(difluoromethyl)-4- in 119 parts of methanol is added with stirring, and the 10 oxazolidiuone.

methanol evaporated in an air stream. The sticky residue The following salts can be prepared by replacing the is vacuum-dried, triturated with a small amount of warm 2,2,5,5-t6trflklS(diflllofomethyl)-4'0XaZ011d1I1011e and P benzene, filtered to remove traces of unconverted oxazolitassium hydroxide of Example 8 with equivalent amounts dinone, and air-dried, leaving the sodium salt of 2,5-bisof the oxazolidinones and bases shown below in Table I.

TABLE I Example Oxazolldinone Base Salt product I 2,2,5,S-tetrakls(dlfiuoromethyl)-4-oxazolldlnone l. Dlmethy1amlne 2,2,5,fi trgakisqlfiuoromethyl)4-oxazolidinone, dimethyl- 81111110 um S8 10 do Calcium hydroxlde 2,2,fiizfi-tetrakls(dlfiuoromethyl)-4-oxazolldlnone, calcium S8 11 do Sodium carbonate 2,2,fi,t5-tetrakls(difluoromethyl)-4-oxazolldlnone, sodium SB, 12.. 2,5-bls(d.lfluoromethyl)-2,5-bls(trifluoromethyl)-4- Triethanolamlne 2,5-bls(diiluoromethyl)-2,6-bls(trifiuoromethyl)-1- oxazolidinone. oxazolidlnone, triethanolammoulum salt. 13.. do Barium hydroxide" 2,5-bls(difluoromethyl)-2,5-bls(trlfiuoromethyD-4- oxazolldinone, barium salt. 14 do Methylamlne 2,5-bls(ilildrluorometht3;l1)i2,5-bis(t{ifiuoro?ethy1)-4- OXZLZO 1110119, me y 8111111011 um S8 15 2,5-bis(chlorodlfluoromethyl)-2,5-b1s(trlfluoro- Ammonia 2,5-bls(chlorodlfioromethyl)-2,5-bls(trlfiuoromethyD-4- methyl) -i-oxazolldinoue. oxazolldlnone. ammonium salt.

(difluoromethyl) 2,5 bis(trifluorolnethyl 4 oxazoli- Substitution of the polyfiuoroketone(s) in columns 1 dinone, which can be formulated and applied as described and 2 in the rocedure of Example 3 yields the oxazolidihereinafter. none(s) shown in column 3 of Table II:

TABLE II Example Column 1 Column 2 Column 3 16 CICFzCOCFzCl ClF2C 0 \ll /C Na o1Flo o N CFzCl 17 CICFzGOCFzCl HCFzCOCFa OlF C 0 F30 0 \l? /C No. /C Na olFlo-o IIV plus HFzC-O r l -CCF: -O-CF2CI CF2H CFzCl 18 HCFzCOCFzH ClCFzCOCF2C1 HF1O\(I C1FzC\([.?

d Na Na nFlo-o N plus olFlo-o l re -CC F201 -CCF2H F261 FQH 19 HCFZCOCFZH HOFzCOCFa EF;O\(|? F3C\([? /C 2 Na /C\ Na Hmo-o N plus HFzC-C Iv -CCF;H -C--OF H F3 FgH 20 HCFzCOCF H CICFgCOCFa HF;C\(|? C1F C\([? /('3 Na /C Na Hula-o N plus Flo-o N $--(:JCF:C1 JJCF:H

CFa F H 21 HCFZ COCF H CFQCOCFS HFgC\IO F3O\ d Na d Na limo-o N plus F C-C 1 1 O I -CF3 OCCF H TABLE IIContinued Example Column 1 Column 2 Column 3 22 HCFZCOCFQH uorlcocrsci HF1C\% HF=C\() NW Nae} HF -C N9 plus 01F20-0 N6 CF2Cl ob-0F2H FzH F211 23 H0F000F3 clcrlcocra HF,C\:) F3C\%) 0 Na 0 Na FaC-C N plus ClFzCO N -0ri01 CFs Fa FQH 24. HCFzCOCF! 010F2000F201 Flog 01F.0 c

Nae; Nae Eric-0 N9 plus 0m0-0 N9 c-0 F201 o i-0 F3 21 101 crzn 25 Honcoom ucrlcoorzci F3c o1Fic I Nag HFzC-C N9 plus uric-0 N9 -0 0 F201 B CF.

CF2H lFzH 2s ClCFzCOCFa 010130001301 F c 011mg Nae; Nae C1F1O-O N9 plus 01F2o-0 N9 J-CF2Cl -c-0F3 CFaCl FzCl UTILITY EXAMPLE B The salts of this invention are useful as flame-proofing agents for paper and textile products. For example, solutions of metal or quaternary ammonium salts in acetonitrile can be used to impregnate paper or cellulosic fabrics with the salt to reduce their flammability.

All the oxazolidinones of this invention are useful as herbicides, and such utility is specifically claimed in my copending application Ser. No. 839,054 of which this is a continuation-in-part. The disclosure of this copending application is specifically incorporated herein by reference.

There follow some examples showing the use of compounds of this invention for herbicidal purposes:

EXAMPLE A Percent (wt.) 2,5-bis(difiu0romethyl) 2,5 bis(trifluoromethyl)- 4-oxazolidinone Partially desulfonated sodium lignosulfonate 3 Dicotyl sodium sulfosuccinate 1.5 Kaolin 45.5

Percent (wt.) 2 difluoromethyl 2,5,5 tris(trifiuoromethyl) 4- oxazolidinone 25 Oleic acid ester of sodium isethionate 3 Polyethoxylated nonylphenol l Diatomaceous silica 71 EXAMPLE C Percent (wt.) 2,2,5,5-tetrakis(difiuoromethyl)-4-oxazolidinone Partially desulfonated sodium lignosulfonate 3 Dioctyl sodium sulfosuccinate 1 Finely divided silica 1 The above ingredients are blended and hammer milled until essentially all particles of active ingredient are 50 microns or less.

Nutsedge and certain annual weeds are controlled in fallow land with 4.5 kilograms of active ingredient per hectare of the above compound. Applied to clean soil or incorporated, by disking, the herbicide provides weed control several weeks, reducing the need for mechanical weed 1 1 control while a crop is not being grown. The chemical is applied in sufiicient volume of water to obtain uniform application (250 to 450 liters per hectare).

What is claimed is: 1. A compound of the formula wherein:

X X", X and X are alike or diiferent and are hydrogen, fluorine or chlorine, with the proviso that at least 20 one X be other than fluorine; and A is hydrogen, Na, or K.

and A=H: 2,2,5,5-tetrakis(chlorodifluoromethyl)-4oxazolidinone.

4. The sodium salt of the compound of claim 1: 2,2, 5,5 -tetrakis (difluoromethyl) -4-oxazolidinone.

References Cited UNITED STATES PATENTS 3,310,570 3/1967 Middleton 260-307 3,461,129 8/1969 Middleton 260-307 ALTON D. ROLLINS, Primary Examiner US. Cl. X.R. 

